Method and means for producing tunes and voices photoelectrically



E. M. JONES METHOD AND MEANS FOR PRODUCING TUNES AND VOICES PHOTOELECTRICALLY Nov. 27, 1951 6 Sheets-Sheet 1 Filed Sept. 22, 1949 Ennentor lame-s,

attorneys.

E. M. JONES 2,576,759 AND MEANS FOR PRODUCING TUYES Nov. 27, 1951 E. M. JONES 3 9 METHOD AND MEANS FOR PRODUCING TUNES AND VOICES PHOTOELECTRICALLY 6 Sheens-Sheet 4 Filed Sept. 22, 1949 JNVENTOR.

fan/mm? 1 W: Jba Es E. M. JONES METHOD AND MEANS FOR PRODUCING TUNES AND VOICES PHOTOELECIRICALLY 6 Sheets-Sheet 5 3mnentor ej- Filed Sept. 22, 19

Nw 27, 1951 E. M. JONES 295769759 METHOD AND MEANS FOR PRODUCING TUNES AND VOICES PHOTOELECTRICALLY Filed Sept. 22, 1949 6 Sheets-Sheet 6 I, ll/

I I I 8 Patented Nov. 27, 1951 2,576,759 @F F ICE METHOD AND MEANS FOR PRODUCING TUNES AND VOICES PHOTUELECTRI- CALLY Edward M. i ones, Cincinnati, Ohio, assignor to The Baldwin Company, Cincinnati, 01110, a corporation of Ohio Application September 22, 1949, Serial N 0. 117,239

48 Claims. (01. 84-418) My invention relates to electrical musical iii-T struments of the photo-electric type, wherein a moving member carries a plurality of pitch tracks dividing incident light into traveling beams, and wherein the traveling beams-on their Way from a light source to a photoelectric cell pass through and scan voicing representations through the agency of which pulsations are set up characteristic of desired fundamental frequencies and desired related harmonics in desired amplitudes for the production of voices.

An object of the invention is the provision of a self-contained, relatively small, and simple generator capable of producing and combining tones within the range of the full tonal scale of a desired keyboard instrument, together with a wide variety of voices.

It is an object of my invention to provide a combination of pitch disc and voice disc of relatively small area but coacting to produce a large number of tones and a large number of voices.

It is an object of my invention to provide a generator in which a division of voices may be obtained, either as respects different parts of the same keyboard or as between different keyboards such, for example, as an organ manual and a pedal clavier.

It is an object of my invention to provide a mode in which tones and voices which are lost by reason of voice shutter divisions may be separately supplied in the same organization of parts.

It is an object of my invention to provide a standardized series of parts making up a selfcontained generator which with or without changes in a pitch disc and a voice disc may be employed either for a single manual keyboard instrument with a divided keyboard, or in tan-'- dem for multi-keyboard instruments including a plurality of manuals and a pedal clavier.

It is an object of my invention to provide in a generator, and particularly in connection with a generator shutter system, a means and method for octave coupling as hereinafter set forth.

It is an object of the invention to provide means and a method for securing the maximum number of voices and tones from a voice disc and a pitch disc containing a minimum number of pitch tracks.

These and other objects of the invention which will be set forth hereinafter or will be apparent tooneskilled in the art upon reading these specifications, I accomplish by that procedure and in that construction and arrangement of parts of which I shall now describe exemplary embodiments having to do with single manual and multi-manual keyboard instruments. Reference is made to the accompanying drawings wherein:

Figure 1 is a top plan view with certain parts broken away, of a generator which I may employ.

Figure 2 is a vertical sectional view of the generator taken along the section line 22 of Figure 1.

Figure 3 is a vertical elevational view of the same generator.

Figure 4.- is a partial plan view of a shutter plate mechanism showing the disposition of the Wire shutter elements and modes of octave coupling which I may employ.

Figure 5 is a partial plan view of a voice disc for a single manual instrument having a divided keyboard, with a portion or the disc broken away to show a part of the pitch disc.

Figure 6 is a diagrammatic representation illustrative of a mode of machining grooves in a shutter plate.

Figure 7 is a diagrammatic illustration of voicing representations designed to produce harmonically related voices from a single pitch track.

Figure 8 is a partial plan view of a voice disc for a two manual instrument.

Figure 9 is another partial plan View of a voice disc for a two manual instrument.

Figure 10 is a partial plan view of a voice shutter arrangement such as may be employed on a single manual instrument.

Figure 11 is a partial perspective view of a voice shutter element.

Figure 12 is a partial Perspective view of a voice shutter element showing means for the attachment of an actuating wire.

Figure 13 is a partial sectional view taken through a shutter plate, voice disc and pitch disc such as a view along the section line i3l3 of Figure 10.

Figure 14 is a partial sectional view through a shutter plate, voice disc and pitch disc taken along the line I l-I l of Figure 10, and showing the operation of the voicing shutters.

Generator assembly This application is related to my copending application entitled Generator for Electric Pulsations of Audio Frequency, Serial No. 108,945, filed August 6, 1949, now U. Patent No. 2,558,- 653 granted June 26, 1951, inasmuch as it makes use of a generator 01' the same general type. The said copending application pertains to the physical organization 01' the main parts of such a generator. I shall first herein describe the generator broadly so that the subsequent teachings herein may be fully understood. Reference is made to Figures 1, 2 and 3, wherein it will be seen that the generator as such is built on the foundation of a shutter plate I. The shutter plate is generally of the type set forth in the copending patent of John F. Jordan, No. 2,506,- 599, granted May 9, 1950, and entitled Shutter Mechanism, and will be hereinafter more fully Centrally of the shutter plate there is a boss 3 or bearing holder with respect to which a pitch disc 5 is journaled for rotation by meansoi a hub 6 and a shaft '5. A voice disc 8 rests directly upon the shutter plate as will be seen most clearly in Figure 2.

A lower can or casing element 9 is affixed to" the shutter plate. It contains a light source 10 in a suitable fitting H, and a paraholicomirror 12. There is an upper can or housing indicated generally at l5, which contains a photoelectric cell [6 and a parabolic mirror ll. It will be understood that'light from the light source [0. reflected by the mirror 52 is passed upwardly through openings in the shutter plate I, through voicing representations on the voice disc 8, through pitch tracks on the pitch disc 5, and is reflected by the parabolic mirror IT to the photoelectric-cell IB.

The pitch disc 5 has a peripheral armature 18 which is directly driven by electromagnetic means including the inside C-core and winding I 9 and the outside E-core and winding is constituting with the armature l8 an-eddy current motor. Within the scope of this invention the pitch disc 5-may be otherwise driven. Where the specific illustrated construction is employed, the 1'.

motor parts are contained within an extension of the canor housing i5-as"shown,-the magnetic cores and-windings being supported thereby.

The photocell I6 and another photocell 22 which is employed in connection with speed control and vibrato tracks .37 and.38 on the pitch disc are supported on a bracket Zia within the upper can or housing l5; .and this bracket may also support other electricalparts such. as a preamplifier and the electric. circuit. elements per- The shutter-plate The shutter plate I hereinabove referred to is of the type having arcuate grooves generally responding, over half their circumferential extent to the circular pitch tracks on the pitch 'disc 5. From the bottoms of these grooves light openings :extendthrough the shutter plateto its lowerside, and arcuate wires operate as actual shutters in the arcuate grooves, moving from side to side "of said grooves in response to longitudinal increments of motion applied to the wires.

The light openings are arranged in series with the several wires simultaneously opening up a plurality of them; and series of" voicing representations on the voice disc 8 are associated with the several series of openings, all as hereinafter more fully described, so that voicing shutters such as the shutter diagrammatically indicated at 22 in Figure 2 may be employed for each voice. The several voicing shutters are operated by wire elements; andprolongations of these elements,

, aswell as the wires attached to the arcuatexwire shutter. elements, are passed throughsheaths forming Bowden transmissions. Certain of the shutter wire transmissions are indicated at 23 in Figures 1, 2 and 3 and certain of the voice shutter transmissions are indicated in Figures 2 and 3 at 24. It will be understood that in the instrument the shutter wire transmission elements will be connected directly or indirectly to respective playirrgkeys of" one or more manuals and a pedal clavier where this is provided, and that the transmissions operating the voice shutters 22, and indicated at 24, will be connected directly or indirectly with stop tabs or other voice selecting devices accessible to the performer. As will be pointed out hereinafter, more than one 'voice shutter 22 may be associated with the samestop tab. Keys and stop tabs have not. been illustratedherein but will :be part of. an instrument console in. which oneor more. of mygenerators will be installed.

The shutter plate. may be made by machining or molding .or acombination of. the two. A. convenient mode ofmanufacture comprisesforming in one face of the .plate, as shownin Figure.13, a plurality of grooves 25 within whichwill. lie the arcuate shutter wires .26, the grooves being wider than the cross sectional dimension of the wires so that the wires can move from side t9 side of the grooves- Deeper, but narrowergrooves ,2! are cut or formed downwardly iromthe bottom of the grooves 25, the said deeper grooves being narrower than the cross sectional dimension of the shutter wires.v Preferably. one edge of the deeper grooves approaches but does not coincide with an edge of the first mentioned grooves, so as to leave a shoulder 28 insuring completion of the cutting ofi of the light when the shutter wire is in closing position. In the opposite side of the plate I machine or mold aplurality of recesses 29 which cut across the various pitch tracks or a desired group of them, and, intersecting the deeper grooves 21, provides the light openings which are opened and closed by the shutter wires. Such an arrangement and mode of manufacture is that described in thesaid Jordan Patent No.2,506,599. 7

It will be understood that the grooves in which the shutter wires lie must correspond substantially with the pitch tracks on the pitch disc 5; and these pitch tracks are circular. However, the passage of. light from the light source to the photocell occurs through light openings located in only approximately one-half of the area of the shutter plate. As a consequence, the correspondence of the grooves with the pitch tracks need occur only in the half of the shutter plate so used. Indeed, the remaining half of the shutter plate has its grooved surface cut away or lowered, excepting for a rim, so as to provide room for the operating Bowden transmission ,connectionsto the several shutter wires. The cut away area of the plate is indicated. generally at 30 in Figure 4. In the light of these considerations it has been found possible, to devisea way of continuously machining the .grooves with a gang tool. Referring to Figure 6, which is a diagrammatic representation, circles 3|, 32 and 33 are concentric with their centers at 34 and are representative of pitch tracks. A spiral dashed line 35 is representative of a spiral .line of cut formed by a gang tool moving progressively radially of a shutter plate blank mounted and rotated by a lathe. Bydecentering the plate in-the lathe so as to establish anew center 35, the correspondence of the spiral with the concentric circles will be as illustrated; and it will be noted that the spiral substantially corresponds with the concentric circles over the entire lower half of the diagrammatic figure. In actual practice the distance of decentering will be determined by the dimensions and spacing of the grooves and pitch tracks.

Dimensions are not a limitation on the present invention. However, one of its advantages is that I may secure the full tonal range desired for a keyboard instrument, plus a large number of voices in a generator of small overall dimensions. Thus in practice I space my pitch tracks on a pitch disc one-sixteenth inch on centers and thus find it possible with a pitch disc of approximately 13 inches in diameter to provide enough pitch tracks to accommodate all of the seventythree notes desired for a single manual organ or all of the sixty-one notes desired for a given manual in a two manual organ plus twelve or thirteen others such as may be desired for connection with a pedal manual, plus a number of replacement tones which may be required in connection with a division of voicing shutter means as hereinafter explained at length. Also on the same pitch disc I may provide two outer, wider tracks, one being for the purpose of speed control, and the other being for the purpose of providing vibrato. In connection with such a pitch disc I provide a shutter plate in which the grooves are .053 inch in width and spaced .0625 inch on centers. The narrower and deeper grooves 21 are preferably .017 inch in width, and the wire shutter elements 26 have a diameter of .028 inch. In the cut away portion 30 of the shutter place the shutter wires 26 are preferably joined to actuating wires of smaller diameter in the sheaths aforesaid, forming the Bowden transmissions, so as to provide room for these transmissions; and the transmissions 23 are preferably carried away from the shutter plate through perforations in the rim thereof as illustrated in Figures 1, 2 and 3. This provides a dust-tight construction, in view of the cans or housings 9 and i5, and their associated parts. The series of Bowden transmissions 24 for operating the voicing shutters may be similarly carried from the shutter plate through holes in the rim thereof, or may be kept underneath the plate and carried, as illustrated in Figures 2 and 3, through a recess or recesses formed in a grooved configuration on the under side of the shutter plate i, which configuration accepts an edge of the lower can or housing 9, there being a dust-tight packing at the juncture of the elements and around the transmissions.

Means for coupling A shutter plate of the wire-and-groove type, as hereinabove generally described and as set forth in the said Jordan Patent No. 2,506,599, has the advantage that movement of a single shutter wire will open up or close a plurality of light apertures about the shutter plate. These apertures may be arranged in a plurality of series associated with various voicing representations so that there is provision not only for the selection of voices but also for the additive combination of voices. However, coupling is a desirable feature of a keyboard instrument of the organ type for various purposes: It is frequently desired that additive voices sound with respect to each other not at the same fundamental frequency but at fundamental frequencies which are harmonically related to each other. Thus,

6 a voice may be desired as a 4-ft. voice, another additive voice as an 8-ft. voice, a third as a 16-ft. voice and so on. Again, ordinary octave coupling irrespective of voice may be desired.

In accordance with my invention I make provision in my shutter plate for coupling. Reference is now made to Figure 4 wherein a shutter plate I is diagrammatically indicated. For the sake of simplicity I have not illustrated the grooves but, instead, have illustrated a plurality of shutter wires which will be understood as lying within the grooves. In this illustration the specified letters C demark the confines of groups of Wires for the respective half tones of consecutive octaves of the musical scale. Seven wires per octave have been shown in the drawing to avoid undue complexity of lines; but it will be understood that the octave of the equitempered musical scale contains twelve semitones and hence in practice there would be twelve shutter wires per octave.

One way of securing the coupling to which I have referred above is accomplished by cutting away or recessing the plate so as to interrupt the continuity of the grooves over certain areas indicated generally in the figure at 39 and40. The grooves are, of course, concentric and will be understood in the figure as formed on the shutter plate in areas generally indicated at 4|, 42 and 43. If any group of shutter wires lying between the indicia C on the drawing are followed, it will be seen that they lie in a series of concentric grooves for one octave in the grooved area 43 and, leaving that area they pass in the ungrooved space 4-0 to the grooves for the next higher octave in the grooved area 42. Leaving that area, they cross over to the grooves for the second higher octave in the ungrooved area 39, and then follow the last mentioned arcuate grooves in the grooved area 4|. One end of each shutter wire is anchored to the shutter plate at the upper right in the figure.

What has been stated above applies to the shutter wires for all of the octaves in the instrument excepting the highest and the lowest. Thus the highest group of shutter wires marked 44 in the figure traverses in the area 43 concentric grooves for the second highest octave provided by the pits disc, then transfer in the ungrooved area 40 to the groves for the highest octave provided by the pitch disc in the grooved area 42. This particular group of wires is anchored to the plate at 45. The group of wires marked 4E does not traverse any grooves in the area 43 but enters the lowermost octave group of grooves in the grooved area 42, transferring in the ungrooved area 3 9 to the next higher octave group of grooves in the area 4|, the wires being anchored at 41.

The voicing representations on the voicing discs will be allocated to series corresponding with series of light openings in the shutter plate lying in the grooved areas 4|, 42 and 43. In my instrument the grooved area 43 may, in general, have light openings arranged in series for what may be regarded as 16-ft. tones; the 8-ft. tones will generally be allocated to the series of light openings in the grooved area 42; and the 4-ft. tones will generally be allocated to series of openings in the grooved area 4|. This is only a matter of convenient terminology since the actual frequency of a tone produced by light passing through any given pitch tract can be determined within limits by other factors, as hereinafter set forth, But the terminology will serve to illustrate an aspect of octave coupling accomplished by this phaseof the :invention. Thusfollowing a .particular shutter wire, say the shutter wire 48, fora C note, itwill first traverse grooves in' the "grooved "area .43 in which area actuation of the wire will open up one or more light openings overlying a'pitch track'appropriate to -65. In the area 42, however, the same wire will traverse a groove and'open-up'one .or more light openings thereinyrelated to a pitchtrack for C-l3l, i. *e., a C note with a frequency of .131 cyclesper second, while'inthe area M it will traverse'a groove and open up one or morerlight openings therein overlying a pitch track appropriate for a C note of 262 .cycles per second.

Where octave coupling is practiced, as hereinabovedescribed, where the pitch tracks on the pitch disc are arranged in accordance with successive octaves of the musical scale, and where in the ungrooved areas the individual wires must skip a distance equal to the radial span of 12 pitch tracks on thepitch disc, it vis well to have them extend'tangentially in the ungrooved areas of the'plate and with thisin mind the ungrooved areas'are so proportioned that a straight line or tangential projection of a shutter wire as it leaves one grooved area, will bring it to the proper position at the beginning of the next grooved area, all as willbe appreciated from' 'the diagrammatic showing of Figure 4.

I am, of course, not restricted to octave coupling and where coupling' at some other harmonic relationship is desired, the configuration of the plate may be such that the various wires will traverse grooves inone grooved portion and then skip to other grooves in the next grooved portion bearing an harmonic relation to the firstgrooves andtheir pitch tracks other thanlan octave relation.

However, there is another way of securing coupling which is also illustrated diagrammatically in Figure 4. If the wire =59 be followed, it will be seen that it traverses in the grooved section 53 a particular arcuate groove, whence in the space Ml it'skips .to the next innermost groove on the shutter plate, again skipping inwardly to the second innermost groove in a grooved section of the plate indicated atz50. This will illustrate the fact that where the radial distance skipped by any particular shutter wire is not great in the radial direction, I am byno means restricted to a tangential extension of the shutter wire in ungrooved areas of the plate.

The pitch disc The various pitch tracks and the speed control and vibrato tracks on the pitch disc are preferably formed'by photographic means; and the pitch disc is preferably a transparentmember bearing the photographic representations. Glass is the materialpreferred by me by reason of its stiffness and dimensional stability. The various pitch tracks, although not specifically illustrated herein, will beunderstood as comprising series of transparent portions foreach track in a generally opaque field, the tracks, of course, being concentric, and the circumferential widths of the transparent portions being limited in accordance with the fineness of the variations representing harmonics in the voice tracks to give proper scanning.

For the most part, the pitch tracks on the preferred form of my pitch disc are arrangedto provide-'a'series of-successive octaves outwardly iromacenter portiQnof-the-disc; each octave as indicated above consistingof 12'pitch tracks." In such an arrangement the number of light openings in each track must bear a whole number relationship to the number of openings in the next track since each trackmust contain a whole number of openings. The exact ratios of the frequencies of the adjacent semi-tones in the equi-tempered scale cannot be expressed in commensurate numbers, as is well known; the ratios will, of course, be approximated more nearly in large whole numbers than in small ones. The frequency produced by any given pitch track will, of course, depend upon the number of light openings in it and the speed of rotation of the pitch disc. For accuracy of representation it is desired that the numbers of light openings in a given track be as small as possible. Nevertheless with .a given and relatively slowspeed of rotation of the pitch disc, it is quite possible to select a whole number series of light openings in the various pitch tracks which will approximate the semi-tones in 6 or 7 octaves of the equi-tempered scale without having the number of openings become too large in the pitch track for the highest note of the series.

My invention is not limited to any particular series and various series may be employed. However, with a pitch disc rotating at a speed of 33.8 R. P. M., I employ a pitch track for the lowest C note of the instrument having 58 openings and this gives me a C note of a frequency of 33 cycles per second. The number of light openings in the pitch tracks scales upwardly to 3712 openings, which at the speed of rotation of the disc gives me a frequency for a high 0 note responding to 2093 cycles per second. An example of a series for a pitch disc which is entirely satisfactory is set forth in the attached schedule, said series being generally similar to that disclosed by Armand F. Knoblaugh in his co-pending application on Serial No. 39,674 entitled Musical Instruments Employing Continuously Moving Members; and it will be noted that as the frequencies ascend, minor whole number corrections have been made in successive octaves to bring about still greater accuracy:

Notes 0f Slots Of Slots In Figure I have illustrated a portion of the pitch disc 5, and diagrammatically represented thereon pitch tracks for a consecutive series of octaves which are six in number, this being suitable for the uses of most keyboard instruments. It will be obvious that by varying the dimensions of the pitch tracks or the dimensions of the pitch disc a greater or lesser number of octave series may be placed thereon. Representative dimensions for a commercial instrument have been given hereinabove. In Figure 5 the six octave series are indicated respectively at 5| to 56 inclusive. Outwardly beyond the last octave series 56 the pitch disc bears a pitch track 31 for speed control purposes and a track 38 for vibrato. The circuits used in connection with these tracks are described in connection with another application noted hereinabove. It is sufficient to note here that the track 31 is used in connection with the photocell 2| and appropriate circuit elements in connection with the eddy current motor 19, 20 to maintain a constant speed in the pitch disc, while the track 38, containing light openings arranged to pass a given point at a suitable subaudio frequency, is employed to vary the constant speed of the pitch disc in a rhythmic manner so as to impart to the reproduced tones a pitch tremolo or vibrato. The tracks 31 and 38 are ordinarily made much wider than the pitch tracks, and with much larger openings in the shutter plate so as to take advantage of a larger amount of the incident light.

Inwardly of the innermost octave series of pitch tracks 5|, there is space on the pitch disc for another series of tracks indicated in Figure 5 at 51. This series may be used for various purposes. For example, in a keyboard instrument having a manual and a pedal clavier, the pitch tracks of the series 5| to 55 may be connected with the keys of the manual, while pitch tracks of the series 5'! may be employed to supply notes for the pedal clavier. Again, in such an instrument, some only of the octave series 5| to 56 may be employed for the manual, and the remainder for the pedal clavier, but in this instance it may be desirable to supplement the range either of the manual or of the pedal clavier, in which event pitch tracks of the series 5'! may be emplayed for this purpose.

But in an instrument where the pitch tracks lie very closely together radially and the toleranoes are small, the division of pitch tracks either as respects a single manual, between different manuals, between a manual and a pedal clavier, or between difierent voices (all of such divisions involving a division of voice shutters as hereinafter more fully taught) one or more pitch tracks may lie at the point of division of voice shutters where neither shutter can be relied upon accurately to cover the particular pitch track or tracks. Where this is encountered, the efiect of one or more pitch tracks may be lost as respects a particular pair of voices or group of paired voices, and hence in the practice of my invention I do not provide light openings at these particular points for these particular pitch tracks. Where this is encountered it is necessary to supply the eifectively missing pitch tracks elsewhere, and in this event pitch tracks of the group 5? are utilized.

Referring to Figure 4 let it be supposed that by reason of any of the divisions mentioned above, the groove representing the note B-62 will fall at the meeting lines of shutters in the grooved area 43, while the corresponding octavely related note B-123 will similarly fall in the area 42 and that there will be a similar obscurement of the pitch track B-24'7 in the area 4|. Under these circumstances I provide in the group 51 in Figure 5 pitch tracks for 13-62, B423, and 3-24? located inwardly of each other in the order named. The wire 49, previously traced, traverses the groove for the inner pitch track, 13-62, in the area 43, then the next inward pitch track groove in the area 50 for 13-247. If I desire to extend certain voicing series to employ a pitch track which may not otherwise be used in conjunction with other voicing series because of shutter divisions, the wire 49 may be coupled to the wire 58 for the normal 13-62 groove as shown at 59.

Voice shutter arrangements In Figure 4 there are certain dotted line representations indicative of series of voice tracks on a voice disc. These are generally directed so as to cut across a plurality of the pitch tracks on the pitch disc. Most of them have an extent sufficient to cover a plurality of octaves; an exemplary arrangement is a group 60 of them which are only one octave in extent. Another exemplary one 5| is four octaves in extent. Still others are interrupted at a point intermediate their length. For example the voice track group 62 extends inwardly over a range of notes from 0-2093 to 0-131, while continuation marked 62:; extends inwardly from the semi-tone next below B-l23 to 0-33, and picks up the semi-tone B-123 in a pitch track of the group 51 hereinabove discussed. The voices produced by the voice tracks in the sections 52 and 62a may be the same or different; but in the particular embodiment, as will hereinafter be more fully explained, one may be desired without the other, or both may be desired simultaneously, and hence different voice shutters will be required for the sections 62 and 62a, which shutters may be operated simultaneously or independently. Finally, I have shown a pair of voice track series 63 and 64 which, in the particular embodiment, are located very close together, and this gives rise to a particular problem in the provision of voicing shutters. The series 63, 54, may also be divided intermediate their lengths as hereinabove described.

I have already indicated the provision of voice channels or recesses 29 in the underbase of the shutter plate I, and the association of voicing shutters with these channels. The light passing through the pitch disc, the voice disc and the shutter element is in parallel beams, for which reason the voice shutters need only be relatively elongated, pivoted panels which in one position do not obstruct the parallel beams passing through any given series of voicing representations, and in another position act to cut them off. Various constructions may be adopted for the voice shutter. A simple and convenient one is illustrated in Figures 10 to 12 and 14. Here a voice shutter 22 is an elongated strip of metal, preferably darkened as to surface so as to be non-reflective, and provided along one edge with turned up ears 65 perforated as at 66. Three posts 61, having similar perforations, are threaded into or otherwise mounted on the underside of the shutter plate I, as will be most clearly appreciated from Figures 10 and 14. The shutters 22 may conveniently be pivoted on the posts by means of a wire pintle 58. Where two or more shutters are in alignment for use with a divided voicing series, as at 22 and 22a in Figure 10, the

samezpintle EST-H1313; serve i-forz-ai plurality-of; shutterss. Thetendsaof the-shutters will. be-iproperly configurediito .followx-thei pitchtracks :as. will; be

evident lfromiFigure 10.

The: wire elements for actuating: the voice shuttersmay bepivoted to them at points remote fromitheir ipivota-l ;connections with the posts *61 in any: suitable way; One inexpensive; simple, but positive way is illustrated in-Figure 12, where the-:voice shutter= 22.5is-slctted-asat 59, slitted as at lii, an-dindented :asat-li and i2: A wire actua-tinglelement lt having a turned over end Hl'may be engaged with: the-shutter from the opposite sideeandl-then swung over to the-:positionillustra-ted in Figure 12, whereupon a pivotal connection will be formed.

It is desired to provide stops for the voice shutters intheir closed position; and to this end-.1 .-attach .to theshutter plate I post-like :stop members Es-having felt pads w form-i-ng abut-r mentseengagingzthe shutters 22 at one end-when they-:are-sin closed position, the pads .76 insuring q uetoperationof the shutters. 1

ImF-ig-ure 14-I haveshown at 29a asvoicecha-n- 11811015 more.-than usual width-anddesigned to accommodate *the .close1-y:- juxtaposed voicing series. 63;; fi l-,shereinabove described; In -providing ShHttGISvfOI these-series, I: adopt a.- construction shownin Figure 14a Here-there "is a "shutter 52% fen. theseries 63 :or; parts thereof. This; shutter swingsitowardr. the element" I in" approaching closediposition; A second voice shutter 220; for theser-ies 614 or:.parts thereof, is arranged to swing inwardly: or toward themain shutter plate I in approachingitheopen position. As) will heappreciatedfiromthe dotted line 'showing in: Figure. -14; theedge of -the-.voice-'channel 29a will serve as.-a stop fcrthe ?voice shutter :220 in open posie tion. Imorderto' provide-a-stop for-rit'in closed positionl mountFa-bracket 11 :on the plated and provide an"; arm-like abutment 18; fort-the voice shutterr The, arrangement .just describedihas the advantage that both shutters 2 Ebfilld'IZC' may be operated by wire-lilce operating, elements ex-e tending :in- :the'same direction.

The;particulararrangement of voice shutters may bewvaried' as desired; lathe-exemplary; instruments:-to.:-which this case relates there is a seriesaof'. voice shutters 22d taking care of the short voicing. representations of the series 60. The divided:voicingseries '62; 62a will be taken careaof by voice:- shutters 22c and 22 and other divided series-Will be taken carerotina' similar manner; Thejuxtaposed series 63; 64, willbe taken care ofaashereinabove describedibyvoice shutters-22b. and-22c;: and their counterparts 22g and 222k. It will alsobe-noted in Figure10'ithat therezzis a shutter-19=for anopening- 80in the main-zshutter plate I, which opening permits passage-of light'throughvibratotrack 38-on the pitchdiscr Another opening-"8:! inthemainshut templates! :permitspassage of lightthrough" the speed control track- 37; but since speed control willsa-lways be in operation, no shutter need be provided. for this opening: The vibrato shutter will; oficourse; be: connected to a suitable stop tab,-,or control knob; on'theinstrument; the latteritogether with-theshutter wiproviding means foristeplessw control of theextentof the vibrato. It m-aybe-noted'thatthevoicing shutters of the series 2211" are made progressively longer so that their: wire operating elements can come away fromtthemdn sid' by side relationship. This is showntin Figure 10. Other modifications may beimade withoutdeparting from the'scope-of my i2 inventiom as: to the shape; arrangement; construction: and 1 mode; of: operation of the s voicing shutters.

Voice discs In,:the:perferred embodiment of my invention the voice: disc ;is: transparent element having a generally opaque-coating. The individual voice tracks-p-thereoni are transparent areas following theconcentric arcuate disc position of theseveral pitch tracks: to which they pertain and varying throughout their entire" lengthteither. imareaior in: transparency so as to .1- impart variations; to the; moving beams producedv .by the transparent areas. ofzitherrotating :pitch disc. lzpreferatoiuse a voiceidi'sc of-glass; by reason :of .its *dimensiona-l stabilitmiand to employincconnection' therewith a:photographic-representative of the opaque areas and: the transparent: areas hereinabove: mene tionecl; The: individual voicing: representations will usually besa; pluralityi-of cycles:long,r. an :ar& rangement which iSFDIGfEII'GdTbY me"for:-several reasons: In thefirstiplace -a: voicing represent'a'e tion severalecycles :inlengzthfizpermits' the use :of a; plurality of. traversing; beams and"; hence' a greaterfquantity' of :light incident oni-the iphoto; cell' ltsperrnote per'"voice; In the second place, the use: of: a plurality 'ofZbeams' simultaneously pen-noteper voice diminishes extraneousznoise due to imperfections-in the'ipitch. tracks.

While there-will 'beonanykeyboard instrument a general, over-all volumeccontroliassociated.with' theaamplifier; it willibe understood thatai general .difierence: in: the sound level of" di'fierent voices "may be desired; some voices "soundingbest as; soft" voices while others are' preferably of greater ivolume;v This" may be. accomplished by soiforming; the voice disc initially: as to provide greater?variation intransparency in the voice track'representations for loudzvoicesthanin those forzsoftivoices:

Theiopaque; area surroundingzeach' individual voice: representation on the voice disc will act as :a' .window therefor, so that as one moving .beam

enters the voice representation another: relieves it. Thusthe perforations for the passage of light iirzthe main shutter plate do notneed to serve aszwindowsxand'hence'do not have to be made with sufficient accuracy for that" purpose.

The general-design ofthe main shutter plate, theunote shutters, individual *or coupled, and the voicing shutters willibe appreciated from the desoriptiorr above;v It will be understood further that; in the: embodiment shown there-will 'bea series :of light openings in themain shutter'plate lifOl'FBflQ-hiSGIiQS or voicing representations on theivoice disc, that therewill' be a 'voice channel on the-under surface of the main shutter plate lrfor such series, that one or more voiceshutters wil'lbeassociated with each such series, and that, theseries of voicing representations on the voice disc-wilfmatch up with the series of openings; and shutters, on the main shutter plate; The particular arrangement illustrated in the figures of thisapplication is a convenient one for commercial instruments, but is not otherwise limiting andmay be considerably varied within the" space limits of any particular generator The nature, moreover, of the particular. voicesrepresented on the voice disc isnot a limitation'on'th'e present invention. The specific voices.

may b'e'any desired for the uses of a particular instrument-and; indeed, on any giveninstrument the voices may be changed if desired by substiti tin one voice, disc'for another in the generator. Voice discs may be otherwise made; but I prefer to make them for my instrument by first producing a master record photograhically by varying beams of light in accordance with the electrical pulsations of a generating apparatus in which I can control the frequency and volume of the fundamental and the amplitude and phase of a plurality of harmonics which may be varied both as to amplitude and phase and as to volume. In this way the characteristic tones of existing instruments can be duplicated and other tones can readily be created. From the master copy other voice discs can be made by photo- I graphic reproduction. A voice disc in my particular generator is suported by the main shutter plate I and serves to close the grooves therein containing the shutter wires 26 for the individual notes. It has a central perforation which fits over the bearing holder 3 (Figure 2), which therefore serves to center the voice disc.

The rotative position of the voice disc may be fixed by clamps or other suitable means (not shown) engaging its periphery.

Where a particular pitch track is not usable, or lost, by the juxtaposition of the edge of two voicing shutters pertaining to the same voicing series, as hereinabove described, the voice track of the series for the particular "lost note will simply be omitted or blacked out on the voice disc. This makes it unnecessary to provide a variation of the shutter structure to take care of this situation.

I have hereinabove indicated that the voicing series pertaining to the grooved area 43 of the main shutter plate I may, if desired be so-called 16-foot voicing means divided or not as desired. The main voicing series such as the series BI, 52, 63 and 64 in the grooved area 42 of the main shutter plate may be S-foot series, while the series of voicing representations 82 in the grooved area 4|, divided or not, may be so-called 4-foot series. In the exemplary embodiment the particular series designated in Figure 4 at 83, which lies in the area 4|, is intended for use as a 2foot series. Also, the short series designated at 60 which lie in the grooved area 42, is used for 4-foot and 2-foot voices. It will be noted, however, that these particular series are juxtaposed to the same pitch tracks which are employed for 8-foot and 4-foot voices of the same frequencies as represented by the occurrence of transparent areas in the same pitch tracks. The respective octave difierences between the 16, 8, and 4-foot voices is taken care of by the octave coupling accomplished on the main shutter plate as hereinabove described. But this is not true of the octave differences between 4-foot and 2-foot voices, or the double octave diiferences between 8-foot and 12-foot voices in the particular embodiment shown. While it is within the scope of my invention to provide additional stages of octave coupling as will be readily apparent to the skilled worker in the art in the light of these teachings, there is another way of obtainin octave relationships which I make use of in the exemplary embodiments herein illustrated.

It will be understood that in my instrument the voicing representations control the fundamental frequencies of individual notes as well as their harmonic contents. In Figure 7 I have shown at 84 a simplified voice representation of sine Wave form having a periodicity or fundamental frequency represented by the distance between dot-dash lines 85 and 86. But I have also illustrated directly therebelow another simplifled sine wave voice representation 81 having a cycle length represented by the distance between and 88 or 88 and 86. If a light beam traverses the voice representation 84 a series of light beams spaced apart the distance between 85 and 86 traverse voice representation 84 at a particular speed and then impinge on a photocell, the light so impinging will be caused to fluctuate at a certain cyclical rate. If however the same beams moving at the same speed traverse the vioce representation 81 the frequency of the cyclical variations will be doubled. I have shown also a third voice representation 89 in which the variations are half the length of those in 81 and one quarter the length of those in 84. The same beams traversing the voice representation 89 at the same speed will produce cyclical light varia tions having a frequency twice or four times the frequency of the previous cases respectively.

While the voice tracks in Figure '7 have been shown as simple sine wave tracks, it will be understood that they may incorporate periodic variations additionally imparting harmonics of selected amplitude and number. In order to produce a successful result under these circumstances it is only necessary that the effective width of the transparent areas in the pitch track be narrow enough to scan the variations of the voice track properly. Thus within certain limits it is quite possible to secure 4 foot or 2 foot voices, for example, from pitch tracks which would normally produce 4 foot or 8 foot voices if they were employed to scan voice representations having cyclical variations equivalent in length to the distance between the transparent areas of the pitch tracks. In the particular embodiment of my invention I employ these principles in connection with the voicing representations of the series 88 and B0.

The representations specifically indicated at 68a are used to extend the series 83 an additional (higher) octave. Since the latter represents a 2-foot voice in the normally 4-foot sections 4|, it may be composed of double wave forms as shown at 81 in Figure 7. It will then follow that the group 60a will be quadruple wave forms, such as 89, since they must represent a 2foot voice in the normally 8-foot section 42. It will be obvious then that it will be desirable that voice shutters corresponding to areas 83 and 60a be actuated by the same stop tab. Their respective actuating wires may be interconnected at the actuating stop tab, or in any suitable manner. A preferred construction is disclosed in a copending application in the name of Merton D. Corwin, entitled The Construction of Photoelectric Organs, Serial No. 181,630, filed August 26, 1950. In a similar manner, other voicing shutters in the group 22d will be operated simultaneously by the stop tabs connected to the voicing shutters corresponding to the series 82, so that the 4-foot voices represented thereby may be extended an additional (higher) octave. The areas 60b-69d, as pointed out above, will be double wave forms since they relate to 4-foot voices in the normally 8-foot area 42.

The specific nature of the voices involved does not form a limitation on the invention, and may be an desired.

General voice arrangements One of the objects of the invention is to provide a generator assembly which will serve the purposes of a variety of keyboard instruments and which, in that function, will be as nearly standardized as possible. By a variety of keyboard instruments; Ifi mean; those: ranging; from single keyboardrzinstruments (usually without any; pedal clavier;-.although a pedal clavier maybe ."added. if desired). to. plural:keyboardiinstruments which also-includear pedalclavier and. which have both a; large number of voicesxand a-wide variety of voices.- The constructional features 'hereinabove described enable meto accomplish this;v

A single manual instrument; especially one without a pedal iclavier; will normally have a dividedkeyboard with provision for securing the same: or. diirerente voices, in the bass and treble sectionszaswell as theeprovision of voicesindividual to the-:two sections, and diifering as to number: In; Figure-.511 have. illustrated an exemplary-arrangement.iora single manual instrument ofthe divided keyboard type. Assuming that .the inward sections of any divided voice series on the. illustrated .voice discare-associated with shutterjwires connected tothe playing keys in the bass vsectionof the manual or keyboard and the. remaining portions of these sections plus others have their shutter wires connected'to. the keys in thetreble section,.it .Will be noted. that-the. par.- ticular. arrangement illustrated provides the following;

O'nesingle-octave-16-foot voice for the bass sec tion;

Threetwo-octavefi foot voices 'for the bass section;

Three-two octave 4-foot voices-for the bass section;

Two'four-octave '16=foot voices 'for the treble sectiOn;

Four 'four octave 8-foot' voicesfor the treble. section;

Three'four-octave 4-f0ot-voicesforthe treble'sec tion, and

One four-octave2-foot voice for the treble section.

A'greaterorlesser numberoi voicesrmay be provided by increasing or 'diminishingthe-t number. of series of voicing" representations and shutter mechanisms 'in'. the light of the teachings above. The point .of divisionibetweenivoices maybe varied by varying :the respective: lengthsaoffthetwo voice shutter plates :1 appropriate to any particular voicing series $012.5 to-changeeither thegpointof divisionin the. keyboard. itself fonall .voices or the points of divisionof different voices as respects the same-.keyboardi Thegvoice disc arrangement illustrated in Figure;;is.also appropriate for .useinasingie manual instrument having aypedallclavier: In such an instrument the-extent of the. keyboard is. usually lessrthan thatoflan. instrument :having no pedal clavier. Where. a pedal iclavienris employed; the shutter 5 wires and voice: shutter mechanisms :for those-voice serieshithertO; referredito. as:.con= nected tothe bass section will be connected to the pedal clavier, and; the shutter wires: and: voice shuttersior the remainder" of thetvoice sections will be connected to; the single manual. keyboard;

In:plural manual instrumentsih'aving' alsoa' pedal clavier, I prefer to employ two generators one :foneach: manual. Each; of these generators will have: whatzm'ay be; calleda: treble: section which will be connected through the appropriate shutter wires to the playing keys of..one of the manuals, while the voicing shutters for the same voicing series will be connected'to stop tabsappropriate to; that manuaL. What has herein-.- above been referred .to as the :bfiSSZSBCtiOH-VOiClIlg series. will be --connected in' thisinstance: through theappropriateashutter wiresltmthezpedal clavier;

In; Figure 18.: I have-s; illustrated. diagram matically.

a voice disc arrangement for. the-- great organ manual of" a two. manual instrument? The: lines of divisionbetween the :sections of divided. voice series in this instance have atdiiferent placement from the-linesof .division .in the single manual arrangement of'Figure 5. It will be noted. that the particular arrangement of Figure 8- provides forthe five' octavesnf the great manual:

One 2-foot' voice.

Four 8-foot voices,

Three ii-foot voices; and One 2'-foot.voice.

There-is provided-by this-voicing disc, for-use in connection. with the, pedal clavier:

Three one-octave 16-foot voices (in area 32) and Three one-octave S-foot voices (in area ii).

The arrangement of the voice disc for theswell manual generator is substantially thesame and is partially illustrated-inFigure 9. This voice disc and the generator in which ,it is, located will furnish the same numberofvoices for the swell manual as that setforth above,qtogether. with voices. for the secondoctave of the pedal clavier (usingzvoicingmepresentations .of' the type Bl in Figurefl);

Since different SpBCifiC,VOlCBS.a1e usually desired for the; great ,and swell manualsof i an .efiective. instrument, the. voicing. discs for. the. two. generators in a two manual instrumentzwill be of the .instrument.

Wherethe lines .of division betweenparts of voicing series. differthe .lost? notes will likewise differ... However, extra pitch tracks. inthe group 51'. (of Ffigurefi)v maybe provided forall oithese lost? notes, andthe. only v otherv difference will 1ie. in the noteshutter wires. at the-inside of the mainshutter plated and the. manner inwhich these are\ connected .to the Bowden transmissions orwith othershu-tter wires.- This isalso a matter which may be taken .care. o:f;in assembly.

Thus, it'willbe seen that I have. created a standardized-design: of generator in which the exception of the. voice discs, certain of the voice shutters: and ,two .or: three 'of the innermostnote shutter wires, all parts-are standard andinvariable, while this standardized mechanism will meet the; needs of-a. Wide variety of keyboard instruments.

It willbe-understood that asmanu-als, beyond the great and swell manuals hereinabo-ve referred to, .are.added to a complex organ, additional generators of mi -standardized design maybe added; difieringfrom-those described above only in their voice discs which may be-altered to providestill other voices.

It will be apparent also :thatthe standardized construction to which referencehas beenimade, permits.-. awide variety of modifications to be accomplished andrwithoutalteration oiitheinain parts of the structure to adapt any particular instrument to specialized uses.

Modifications may be made in my invention without departing from the spirit of it. Having described my invention in certain exemplary embodiments, what I claim as new and desire to secure by Letters Patent is:

1. In a photoelectric musical instrument a shutter plate having in one surface grooves for containing shutter wires and openings extending through the plate from the bottom of said grooves, shutterwires in said grooves, said wires being capable of moving from side to side in said grooves to cover and uncover said openings, and means to so move said wires, said grooves being interrupted at intervals and said shutter wires passing, where said grooves are interrupted, from one groove to another groove which is not a prolongation thereof.

2.,The structure claimed in claim 1 wherein said groove have an arcuate configuration in said plate and in which said wires follow arcuate paths in said grooves and substantially rectilinear paths where said grooves are interrupted.

3. The structure claimed in claim 1 wherein said grooves have an arcuate configuration in said plate and in which said wires follow arcuate paths'in said grooves and substantially rectilinear paths where said grooves are interrupted, and in which said wires serve to cover and uncover a plurality 'of openings per groove in the uninterrupted sections thereof.

4. In a photoelectric musical instrument a shutter plate having arcuate grooves of substantially concentric arrangement in said plate, shutter wires lying in said grooves, said wires serving to cover and uncover light openings in the bottoms of said grooves by moving from side to side in said grooves, and means to so move said wires, said grooves being interrupted in common substantially radially directed areas so as to provide grooved areas and ungrooved areas on the surface of said plate, said shutter wires traversing the grooves of a grooved area arcuately, and passing rectilinearly in an ungrooved area to meet other grooves of the next grooved area, lying in said last mentioned grooves in an arcuate fashion.

5. The structure claimed in claim 4 wherein the grooves are arranged in a plurality of series of 12 concentric grooves each, representing the semi-tones of the equi-tempered musical scale and wherein in said ungrooved areas said wires pass from a groove for a particular frequency in a first grooved area to a groove for an octavely related frequency in the next grooved area.

6. In a photoelectric musical instrument of the type having a grooved shutter plate with light openings extending therethrough from said grooves and wires lying in said grooves to cover and uncover said light openings, coupling means comprising an interconnection between wire portions lying in different ones of said grooves whereby said wires are actuated simultaneously.

7. In a photoelectric musical instrument of a type having a rotating pitch disc with concentric pitch tracks thereon and a voice disc with a plurality of series of voice representations responding to said pitch tracks in position, a shutter plate having a surface provided with grooves responding to said pitch tracks in position, having series of light openings therethrough from the bottoms of said grooves and responding in position to said series of voice representations, and having ungrooved areas interrupting said grooves at intervals, and shutter wires lying in said grooves re-= spectively and passing in said ungrooved areas from one set of grooves to another set of grooves progressively.

8. The structure claimed in claim 7 wherein said pitch disc has a plurality of said pitch tracks arranged progressively in the order of the semitones of a plurality of octaves of the equi-tempered musical scale, and in which said shutter wires pass from grooves in said first grooved area related to certain of said pitch tracks to grooves in a succeeding grooved area related to pitch tracks an octave higher than the first mentioned pitch tracks.

9. The structure claimed in claim 7 wherein said pitch disc has a plurality of said pitch tracks arranged progressively in the order of the semitones of a plurality of octaves of the equi-tempered musical scale, and in which said shutter wires pass from grooves in said first grooved area related to certain of said pitch tracks to grooves in a succeeding grooved area related to pitch tracks an octave higher than the first mentioned pitch tracks, and in which a plurality of different shutter wires lie in continuations of the same grooves in different grooved areas of said shutter plate.

10. The structure claimed in claim 9 including voicing shutters on the side of said plate opposite said grooves and acting to cover and uncover the several series of voicing representations on said voice disc.

11. The structure claimed in claim 9 including voicing shutters on the side of said plate opposite said grooves and acting to cover and uncover the several series of voicing representations on said voice disc, and in which the voice shutter for at least one of said series is interrupted intermediate its length to form two separately actuable voice shutter parts.

12. In a photoelectric musical instrument of a type having a rotating pitch disc with concentric pitch tracks and a voice disc bearing several series of voice representations, the series being directed transverse the pitch tracks, voicing shutters for said series divided intermediate their ends into a plurality of separately operable portions, the series of. voicing representations provided with such shutters being divided into different voices for the different shutter portions.

13; A shutter plate having a plurality of substantially arcuate grooves formed in one face thereof, the opposite face of said plate having a plurality of recesses traversing said grooves, said plate having apertures opening from said grooves into said recesses, flexible, strand-like shutter elements lying in said grooves and movable to cover and uncover said apertures, and other shutter elements associated with said recesses to cover and uncover a plurality of apertures associated therewith, one at least of said last mentioned shutter elements being divided transversely into a plurality of separatel operable portions.

14. A shutter plate having a plurality of substantially arcuate grooves formed in one face thereof, the opposite face of said plate having a recess traversing said grooves, said plate having a plurality of apertures opening from said grooves into, said recess, flexible, strandlike shutter elements lying in said grooves and movable to cover and uncover said apertures, and a pair of shutter elements associated with said recess, each independently movable to cover and uncover different partsof apertures associated with said grooves.

15. The structure claimed in claim 14 wherein i ioricg apertures opening from said grooves into said recess, flexible, strand-like shutter elements lying in said grooves and movableto cover and uncover said apertures, and a plurality of shutter elements associated with said recess to cover and uncover each less than the full number of said a ertures.-

17. A pitch disc for use with a voice disc having divided series of voicing representations thereon and divided voicing shutters, said pitch disc having pitch tracks concentrically arranged there-on, said pitch tracks comprising a first group arranged successively in accordance with the semi-tones of a plurality of octaves of the equitempered musical scale, and a second group of" pitch tracks thereon some at least of which are for the same frequencies as pitch tracks in the first group to supply notes lost at the pointsof division of said series of voicing representations.

18. A pitch disc for use with a voice disc having divided series of voicing representations thereon and divided voicingshutters, said pitch disc having pitch tracks concentrically arranged thereon, said pitch tracks comprising a first roup arranged successively in accordance withthe semi-tones of a plurality of octaves of the equi-tempered musical scale, and a second group of pitch tracks thereon some at least of which are for the same frequencies as pitch tracks in a the first group to supply notes lost at the points of division of said series of voicing representations, in combination with shutter means of wireand groove type, and wherein wire shutter elements lying in separate grooves for the same frequencies are interconnected for concurrent operation. V

19. A pitch disc for use with a voice disc having divided series of voicing representations thereon and divided voicing shutters, said pitch disc having pitch tracks concentrically arranged thereon, said pitch tracks comprising a first group arranged successively in accordance with the semi-tones of a plurality of octaves of theequi-tempered musical scale, and a secondgroup of pitch tracks thereon some at least of which are 55 first group to supply notes lost at the points of for the same frequencies as pitch tracks in the division of said series of voicing representations, in combination with shutter means of wire-and groove type, and wherein the grooves of said shutter means are interrupted in groups, with a.

passage of said shutter wires from grooves of one group to'different grooves of the next succeeding group whereby to effect coupling.

20. A pitch disc for use with a voice disc having divided series of voicing representations thereon and divided voicing shutters, said pitch disc having pitch tracks concentrically arranged thereon, said pitch tracks comprising a first group arranged successively in accordance with the semi-tones of a plurality of octaves of the equi-tempered musical scale, and a second group of pitch tracks thereon some at least of which are for the same frequencies as pitch tracks in the first group to supply notes lost atthe points of division of said series of voicing represente tions, in combinatiorrwith shutter means of wireand groove type, and wherein the grooves of said shutter means are interrupted in groups, with a passage of said shutter wires from grooves of one groupto different grooves of the next succeeding group whereby to eifect coupling, and in whichcertain of the series of voicing representations are common to less than the full-number of said pitch tracks.

21.- A- pitch disc for use with avoice disc having divided series of voicing representations thereon and dividedvoicing shutters, saidpitch disc having pitch tracks concentrically arranged thereon, said pitch tracks comprising a first group arranged successively in accordance-with the semi-tones of a plurality of octaves of the equi-tempered musical scale, and a second group of pitch tracks thereon some at least of which are for the same frequencies as pitch tracks in the first group to supply notes lost at the points of division of said series of Voicing representations, in combination with shutter means of wire-and-groove type, and wherein the grooves of said shutter means are interrupted in groups, with a passage of said shutter wires from grooves of one group to different grooves of the next suc ceeding group whereby to efiect coupling, and'in which certain of the series of voicing representaations act to modify moving beams of light produced by pitch tracks on said pitch disc to provide voices having fundamental frequencies greater than the lowest fundamental frequencies derivable from their respectively associated pitch tracks.

22. A pitch disc having pitch tracks thereondivided into two groups, a firstgroup of pitch tracks arranged consecutively in the orderof the semi-tones of a plurality of octaves of the equitempered musical scale and a second group of pitch tracks not so arranged but including pitch track's duplicating as to fundamental frequency certain of the pitch tracks in the first group, in which the pitch tracks of the second group lie concentrically inside the pitch tracks constituting the first group.

23. A pitch disc having pitch tracks thereon divided into twogrcu'ps, a first group" of pitch tracks arranged consecutively in the order of the 1 semi-tones of 'a' plurality of octaves of the equitempe'red musical scale and a secondgroup': of"

pitch tracks not so arranged but includingpitch tracks duplicating as to fundamental frequency certain of'th'e pitch tracks in'the first'gr'oup, in

which the pitch 'tracks'of the secondgrou'p lie concentrically inside the pitch tracks constituting the firstgroup, and in which a pair of additional" tracks arranged concentrically outside-the first group of tracks, one" of said additional pitch track's constituting a speed control'track andthe other a vibrato track.

24. A voicedisc for use'with a'rotatingfpitch' disc having concentric pitch tracks, said voice disc having voicing representations thereon r'esponding to the several pitch tracks and arranged in series traversing'the'said pitch tracks, where V atleast one of the said-series of voice representations" is divided intermediate its length into a plurality of groups of voice-representations for different voices.

25. A voice disc for'use with a rotating pitch disc having concentric pitch tracks, said voice disc having voicing representations thereon re-' sponding to' the several pitchv tracks and arranged in series traversing thesaidpitch tracks,

21 where atleast one of the: said series oi voice representations is divided intermediate its length into a plurality of groups of voice representations for different voices, and in which certain at least of said series traverse less than the full number of said pitch tracks.

26."A voice disc for use with a rotating pitch disc having concentric pitch tracks, said voice disc having voicing representations thereon responding to the several pitch tracks and arranged in series traversing the said pitch tracks, where at least one of the said series of voice representations is divided intermediate its length into a plurality of groups of voice representations for different voices, and in which said last mentioned series contain voicing representations acting to increase the fundamental frequencies of cyclical variations produced in light beams traversing them at given speeds.

27. In a photoelectric generator of the type having a wire-and-groove shutter arrangement including a shutter plate, a voice disc supported by said shutter plate and closing the grooves therein, a pitch disc rotatively mounted on said shutter plate and driven with respect thereto, series of voicing representations on the voice disc traversing the pitch tracks, and voicing shutters acting to select voices, and an interconnection between wire portions traversing different ones of said grooves.

28. The structure claimed in claim 27 wherein certain of the grooves traversed by interconnected wire portionslie opposite pitch tracks for the same fundamental frequency on said pitch disc and wherein certain at least of the series-of voice representations are divided into different voices intermediate their lengths at the points of occurrence of said duplicated frequencies.

29. The structure claimed in claim 27 in which the grooves in said shutter plate are interrupted and in which the interconnected wire portions are continuations of the same wire elements, said wire elements passing from groove to groove in the areas of interruption of said grooves whereby to effect coupling.

30. In a keyboard instrument having a bass section and a treble section, a photoelectric generator of a type having a rotating pitch disc, a voice disc and a grooved shutter plate with wire elements for covering and uncovering apertures therein, the voice disc having voicing representations, and the voicing representations and the apertures of said shutter plate being arranged in corresponding series traversing the pitch tracks, certain at least of said voicing representation series being divided intermediate their length into treble and base portions, the shutter wires traversing said portions being connected respectively to the bass and treble sections of the playing elements of said instrument.

31. The structure claimed in claim 30 wherein said instrument is a single manual instrument and wherein the bass and treble portions of the playing elements of said instrument are divided portions of said manual.

32. The structure claimed in claim 30 wherein said instrument has a manual and a pedal clavier and wherein the treble shutter wires are connected to the playing keys of said manual, and the shutter wires of the bass section are connected to the pedals of said pedal clavier.

33. The structure claimed in claim 32 wherein the grooves of said shutter plate are interrupted intermediate their lengths and in which the shutter wires pass from groove to groove in the areas of interruption to provide coupling.

34. The structure claimed in claim 32 wherein the grooves of said shutter plate are interrupted intermediate their lengths and in which the shut ter wires pass from groove to groove in the areas of interruption to provide coupling, and in which certain of the series of voicing representations are common to less than the full number of said pitch tracks.

35. The structure claimed in claim 32 wherein the grooves of said shutter plate are interrupted intermediate their lengths and in which the shutter wires pass from groove to groove in the areas of interruption to provide coupling, and in which certain at least of the last mentioned series contain voicing representations for producing a fundamental frequency higher than the lowest frequency obtainable from the pitch tracks with which they are associated.

36. In a photocell musical instrument having at least two manuals and a pedal clavier, a pair of photoelectric generators each having shutters on a stationary shutter plate, and a rotating pitch disc with pitch tracks thereon, said shutters being divided into two groups, a first group for providing the semi-tones of a plurality of octaves of the equi-tempered musical scale for one of the manuals, and a second group for providing a plurality of notes for the pedal clavier.

37. In a photoelectric musical instrument having at least two manuals and a pedal clavier, a pair of photoelectric generators each having shutters on a stationary shutter plate, and a rotating disc with pitch tracks thereon, said shutters being divided into two groups, a first group for providing the semi-tones of a plurality of octaves of the equi-tempered musical scale for one of the manuals, and a second group for providing a plurality of notes for the pedal clavier, said generators also having a voice disc with series of voicing representations thereon for imparting voices, certain at least of said series being divided intermediate their lengths to provide in connection with said pitch tracks voices for said manuals and other voices for said pedal clavier and voicing shutters for said respective portions connected respectively with stop tabs for said manuals and said pedal clavier.

38. The structure claimed in claim 37 wherein the shutter plate is provided with grooves responding in position to said tracks, wherein wire shutter elements lie in said grooves, wherein said grooves are interrupted intermediate their lengths, wherein said shutter wires pass from groove to groove where said grooves are interrupted, so as to attain coupling, and wherein grooves for certain of said pitch tracks are traversed by diiferent wires in different parts, certain of said wires having connection to the playing keys of a manual and certain thereof having connection with said pedal clavier.

39. A pitch disc having pitch tracks thereon divided into two groups, a first group of pitch tracks arranged consecutively in the order of the semi-tones of a plurality of octaves of the equi-tempered scale and a second group of pitch tracks not so arranged but including pitch tracks duplicating as to fundamental frequency certain of the pitch tracks in the first group, in which a speed control track is arranged concentrically outside the first group of tracks.

40. A pitch disc having pitch tracks thereon arranged consecutively in the order of the semitones of the equi-tempered scale and a speed accent-e control tra k; thereon arranged: concentrically trio pitch tracks'thereon and avoice disc having several series of voicerepre's'entations', the series being directed transverse the pitch tracks,-voicing' shutters for said series; one of said series being an eXten'sion-of V the voice of another-series} the voicing shutters for said last r'nentionedseries b'eing interconnected for" simultaneous actuation;

- 42.1'n aphotoelectric rnusical instnument dt a typehavinga rotating pitch disc with concentric pitch tracksthereon' anda voice dischaving several series of voice representations, the' several series-being directed transverse the pitchtracks, one of said several series being an extension of thevoice of another of said several series, said one series having a representation of a wave having substantially thesame formbuthalf the wave length of said other series.

43. In a photoelectric musicalinstrument including a pitch disc having a plurality of concentric circular pitch tracks, a shutter plate having a surface provided with arcuate' grooves substantially responding to said pitch tracks in position, each of said arcuate grooves being a portion of a spiral, said spiral having a center oiT-set from the true center of said shutterplate, said shutter plate being recessed on that side having the grooved surface so as to interrupt said spiral, said shutter plate having light openings extending therethrough from said arcuate grooves, wires lying in said arcuate grooves, and means to actuate said wires so as to cover and uncover said light openings.

44. The structure of claim 12 in which a plurality of thesaid several series of voice representations lie in a given sector of said disc, the series making up said plurality being arranged parallel to one another, some of said parallel series being of different lengths whereby the angle defining said sector is smaller than would be the case if the said plurality of series were radially disposed of said disc.

ral'ity of ser ies of voicing representations lie-in agivensector'of-said disc, the-series making up sa id plurality being; arranged parallel to one another;- some or said parallel series being of difierent lengths whereby the angle definingsaid sector is' -smaller than would be the case n the said'plurality o'f seri'es were radially disposed of said disc;-

46. The structure-claimedclaim 4- inwhichthe rectilinear path assumed by a said shutter wire in passing through an ungrooved area from one grooved area to the next grooved area is a tangential projection of the shutter wire lying in an arcuate groove" of" the first mentioned grooved area; 1

47. A -pi'tch disc"ha'v ing" pitchtracks thereondivided into two groups, a first group of pitch tracks arranged consecutively in the order of' the equi-tempered scale and a second group of the peripheryofsaid pitch disc.

48. A- pitch disc having pitch tracks thereon divided into two groups, a first group of pitch tracksarranged consecutively in the order of the semi-tones of a plurality of octaves oi the equi-tempered scale and a second group of pitch tracks not so arranged'but including pitch tracks duplicating as to' fundamental frequency certain of the" pitch tracks'in the first group, in which a tremolo track is arranged concentrically out- "side-the'first group of tracks.

-EDWARD M. JONES.

REFERENCES CITED The following references areof record in the file of this patent:

UNITEDSTATES PATENTS.

Number Name Date 1,986,547 Winch Jan. 1, 1935 2,014,741 7 Lesti s Sept. 17, 1935 2,075,802- D'avis Apr. 6, 1937 

